Manhole Cover Latch Assembly with Padlock Security
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Solution Overview
Problem
Despite their significant weight, manhole covers can be removed by unauthorized personnel, posing risks to infrastructure and public safety, as they are not adequately secured against unauthorized access or pressure-induced events.
Innovation Solution
A manhole cover assembly featuring a latch assembly with a latch housing, latch bar, and padlock configuration that allows for secure locking and unlocking, while also providing a mechanism to manage pressure and prevent damage from sudden events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a manhole cover is made heavy (using cast iron weighing more than 100 pounds), then it is difficult for unauthorized individuals to remove and it stays in place during traffic, but it can still be removed by unauthorized personnel who cause damage to infrastructure
Solution Approach 1:
The manhole cover system is divided into two functional parts: the heavy cover itself and a separate latch assembly. The latch assembly includes a latch bar that engages with the frame and a padlock mechanism that secures the latch bar in place. This segmentation allows the cover to remain heavy for security while adding a locking mechanism that prevents removal without proper authorization.
Solution Approach 2:
The latch bar serves as an intermediary element between the manhole cover and the frame. It translates the securing action into a locked position, preventing direct removal of the cover. The padlock acts as another intermediary that secures the latch bar, creating a multi-stage security system that addresses both the weight limitation and security requirement.
2Reliability
If a manhole cover is made heavy to prevent unauthorized removal, then public safety is improved, but the complexity of the securing mechanism increases when additional latch and padlock components are added
Solution Approach 1:
The latch assembly components (latch housing, latch bar, and padlock mounting features) are integrated directly onto the manhole cover as a unified assembly. This merging reduces the number of separate components that need to be handled independently and simplifies installation while maintaining the security function.
Solution Approach 2:
The latch bar serves multiple functions: it engages with the frame to prevent cover removal, provides a mounting point for the padlock, and acts as a lever for the locking mechanism. This multi-functionality reduces the need for additional separate components, thereby reducing overall system complexity while maintaining security.
3Reliability
If a latch assembly with padlock is added to secure the manhole cover, then unauthorized removal is prevented, but the ease of operation for authorized personnel decreases
Solution Approach 1:
The latch bar is designed to be movable between engaged and disengaged positions, allowing authorized personnel to easily lock and unlock the cover. The padlock mechanism incorporates a key-operated locking action that secures the latch bar in the engaged position but allows quick release when the correct key is used. This dynamic design balances security with operational ease.
Data Source
AI summary
A manhole cover assembly includes a manhole cover supportable by a seat of a manhole frame and a latch assembly. The latch assembly includes a latch housing, a latch bar, and a padlock. The latch housing is fixedly coupled to the manhole cover and defines a channel that extends through the latch housing. The latch bar is coupled to the channel and is slidable relative to the latch housing between a locked position and an unlocked position. The padlock is operatively coupled to the latch bar and is configured to maintain the latch bar in the locked position.